Very simple burgers, with canned tuna given a flavour kick with smoked mussels. I am uncertain about the exact weight of tuna cans in the USA: I used 2 of the solid-pack cans, 170 g each. Do not use shredded or tuna chunks, because it yields so little meat! Use any dry poultry stuffing with a breadcrumbs basis. Because of this dry stuffing the burger mixture needs to stand about 30 minutes (or be prepared hours before if you like) so that the dry stuffing can absorb liquid. Prep time does not include standing time.